P DESIGNED TR I MO E

Issue 3

DESIGNED TO

P R I M EPERFUSION RELATED INSIGHTS - MANAGEMENT AND EVIDENCE

Issue 7

Scien�fic Committee

Name Designa�on

Dr. Kamla Rana HOD – Perfusion Department at Medanta - The Medicity, Gurgaon

P. V. S. Prakash Consultant Chief Perfusionist at Narayana Hrudayalaya, Bengaluru

Bhaskaran Vishwanathan Chief Perfusionist at Madras Medical Mission Hospital, Chennai

Manoj M. C. Perfusionist at Kokilaben Dhirubhai Ambani Hospital,Mumbai

P. Mathavan Chief Perfusionist at JIPMER,

G. Naveen Kumar Chief Perfusionist at Care Hospital, Hyderabad

Atul Solanki Chief Perfusionist at U. N. Mehta Hospital, Ahmedabad

Puducherry

PRIME Newsletter invites new authors for their contribu�on to the perfusion community. If you are interested in volunteering your �me wri�ng an ar�cle, topic of your exper�se and willing to share your knowledge with our readers, we certainly encourage you to do so. We invite everyone interested in joining our team and you can contact us at the email given below. Any amount of �me that you can volunteer in adding to our quality of publica�on will be greatly appreciated. Thank you for your interest in PRIME Newsletter. What are you wai�ng for?

E-mail- [email protected]

Editorial Letter

Mr. Rahul SharmaManager Clinical ExcellenceTerumo India Pvt. [email protected]

Dr. Sandeep AroraDirector Medical and Clinical AffairsTerumo India Pvt. Ltd.

Dear Readers,

We are pleased to present the seventh issue of PRIME to you. PRIME – 'Perfusion Related Insights - Management and Evidence' – is a scien�fic newsletter published every quarter with the help of our editorial board members, and includes latest reviews, guidelines, and expert experiences in rela�on to perfusion strategies.

In this seventh issue, we are happy to present five ar�cles under the sec�on ''Review Ar�cles''. The first ar�cle examines the safety of transesophageal echocardiography while using extracorporeal life support. The second ar�cle highlights the possibility that bubble transgression in membrane oxygenators may be caused by vacuum-assisted venous drainage vacuum. The third ar�cle assesses the management of massive hemoptysis while on extracorporeal membrane oxygena�on. The fourth ar�cle elucidates the ammonia perfusion positron emission tomography in pa�ents with hypertrophic cardiomyopathy. The fi�h ar�cle assesses the efficacy of stress echocardiography versus myocardial perfusion imaging in pa�ents presen�ng to the emergency department with low-risk chest pain.

The ''Expert Experiences'' sec�on covers two interes�ng topics by the experts — criteria for size selec�on of membrane oxygenator for pa�ents with cyano�c congenital heart disease and kinetic-assisted venous drainage on cardiopulmonary bypass for redo mitral valve replacement.

The ''Guidelines'' sec�on focuses on ''Safety devices'' from the American Society of ExtraCorporeal Technology Standards and Guidelines for Perfusion Prac�ce (2013). The ''Latest News'' sec�on deals with the methodology to improve bypass surgery techniques and the best predictor of transfusion of packed cells: Preopera�ve hemoglobin level.

We hope that perfusionists will find these ar�cles interes�ng and helpful. We are looking forward to receive your valuable feedback, comments, and sugges�ons that will help us to work better on our future issues.

Table of ContentsReview Ar�cles 5

Safety of transesophageal echocardiography while using extracorporeal life support 5

Bubble transgression in membrane oxygenators may be caused by vacuum-assisted venous drainage vacuum 6

Management of massive hemoptysis while on extracorporeal membrane oxygena�on 7

Ammonia perfusion positron emission tomography in pa�ents with hypertrophic cardiomyopathy 8

Efficacy of stress echocardiography versus myocardial perfusion imaging in the pa�ents presen�ngto the emergency department with low-risk chest pain 9

Expert Experiences 10

Which is the most appropriate criterion for size selec�on of membrane oxygenator for pa�entswith cyano�c congenital heart diseases: Body weight or high hematocrit? 10

Kine�c-assisted venous drainage on cardiopulmonary bypass for redo mitral valve replacement– A case report 11

Guidelines 12

The American Society of ExtraCorporeal Technology standards and guidelines in individualswith perfusion prac�ce (2013) 12

Latest News 13

Bypass surgery techniques can be improved using synthe�c heart valves, arteries, and veins 13

The best predictor of transfusion of packed red cells: Preopera�ve hemoglobin level 14

Self-Assessment 15

DESIGNED TO

P R I M EPERFUSION R ELATED I NSIGHTS M ANAGEMENT AND E VIDENCE-

5

Safety of Transesophageal Echocardiography while using Extracorporeal Life Support

Source: Nowak-Machen M, Schmid E, Schlensak C, Consferent C, Haeberle HA, Rosenberger P, et al. Safety of transesophageal echocardiography during extracorporeal life support. Perfusion. 2016 Apr 28.

CONC

LUSI

ON

Transesophageal echocardiography is safe in critically ill patients with ECLS — even though there was systemic anticoagulation — during probe insertion, manipulation, and removal.

Introduc�on

Methods

In cri�cally ill pa�ents, refractory to medical management, the use of extracorporeal life support (ECLS) hasmarkedly increased. During extracorporeal therapy, transesophageal echocardiography (TEE) is commonly used to assess the posi�on of the cannula and cardiac func�on. The purpose of this study was to determine whether TEE probe inser�on and removal in systemically an�coagulated ECLS pa�ents was safe as compared to the pa�ents without ECLS and normal coagula�on studies.

It involved an analysis of 87 separate TEE examina�ons in 53 adult ECLS pa�ents. Rou�ne coagula�on tes�ng was performed two hours prior to the TEE exams. Controls (N = 87) were age- and gender- matched pa�ents undergoing periopera�ve TEE without ECLS and normal coagula�on.

SECTION 1

Results

In ECLS pa�ents, overall TEE-associated morbidity was 2.3% and consisted of minor oropharyngeal bleeding (2/87 TEE exams) (Table 1). The pa�ents suffering from oropharyngeal bleeding were administered heparin for anticoagulation and had two or more abnormal coagula�on studies at the �me of TEE. Among the ECLS pa�ents, 79% received intravenous heparin infusions, 6.8% argatroban, and 3.4% epoprostenol. Due to pre-exis�ng bleeding, bleeding complications, and/or deranged plasma�c coagula�on profiles, 10.8% of the pa�ents were not an�coagulated at the �me of TEE.

Table 1: Complica�ons associated with TEE examina�ons

ECLS (N = 87) Control (N = 87) P

Diffuse oral bleeding 2 (2.3%) 0 n.s.

Upper gastrointes�nal hemorrhage 0 0

Esophageal perfora�on 0 0

0 0

Endotracheal tube dislodgement 0 0

Dental injury

The indica�ons for TEE exams in ECLS pa�ents

should be carefully analyzed on a case-by-case basis.

Abbrevia�on: n.s., no significance.

DESIGNED TO


6

Bubble Transgression in Membrane Oxygenators may be caused by Vacuum-Assisted Venous Drainage Vacuum

Source: Nygaard K, Thiara AS, Tronstad C, Ringdal MA, Fiane AE. VAVD vacuum may cause bubble transgression in membrane oxygenators. Perfusion. 2016 May 25.

CONC

LUSI

ON

Vacuum-assisted venous drainage vacuum may cause BT in an oxygenator and this is observed for all the oxygenators in this experiment.

Figure 1: The schema�c overview of the in vitro setup

Safety while using VAVD can be accomplished by using an alarm trigger on nega�ve

pressure in the oxygenator or a pressure relief valve.

restarted, was done using an ultrasonic clinical bubble counter, Gampt BCC 200.

There was a significant increase in bubble count for two of the oxygenators, caused by -30 mmHg of VAVD in the blood reservoir (Affinity Fusion and Inspire 6M). Massive air ingress was observed in two of the oxygenators; caused by -30 mmHg of VAVD vacuum in the Capiox RX25 reservoir and -40 mmHg of VAVD vacuum in the Affinity Fusion reservoir.

Results

Introduc�on

Methods

Vacuum-assisted venous drainage (VAVD) is commonly used to enhance venous blood return from pa�ents undergoing cardiopulmonary bypass. The vacuum can accidentally reach the oxygenator of the heart-lung machine and can draw gas bubbles into the blood. This is called as bubble transgression (BT) and may cause air emboli in the arterial blood line. In order to elude BT and reduce the risk of pa�ent injury, knowledge of oxygenator tolerance to vacuum load is cri�cal. The purpose of this study was to determine how much vacuum a membrane oxygenator can withstand before BT appears.

Four adult oxygenators; Quadrox-i, Affinity Fusion, Capiox RX25, and Inspire 6M were tested in an in vitro setup where VAVD vacuum was allowed to reach the oxygenator via a nonocclusive roller pump (Figure 1). Coun�ng of the bubbles on the arterial line, when the arterial pump was

VAVD controllerBloodreservoir

De-air line

Hydrosta�c pressure on theoxygenator

0.2 µm filter

UltrasonicsensorPVAVD

Roller pump

Pressure meter

Poxy

Pressure lineair/liquid separator Oxygenator

Arterial line

Bubble Counter

BCC 200

DESIGNED TO


7

Management of Massive Hemoptysis while on Extracorporeal Membrane Oxygena�on

Source: Pitcher HT, Harrison MA, Shaw C, Cowan SW, Hirose H, Cavarocchi N. Management considera�ons of massive hemoptysis while on extracorporeal membrane oxygena�on. Perfusion. 2016 May 25.

CONC

LUSI

ON Bleeding complication is a major issue in patients with ECMO. It is safe to disconnect the ventilator and clamp the endotracheal tube with full respiratory and cardiac support by V-A ECMO. Re-hemoptysis can be prevented by an early involvement of interventional radiology to embolize any potential source of the bleed.

Introduc�on

Methods

Results

Veno-arterial extracorporeal membrane oxygena�on (V-A ECMO) is an important procedure in pa�ents with both respiratory and cardiac failure. Since pa�ents must be maintained on an�coagulants, bleeding complica�ons are common. A rare complica�on of ECMO is massive hemoptysis but can cause death if not managed me�culously.

In order to iden�fy episodes of massive hemoptysis, a retrospec�ve chart review of consecu�ve ECMO pa�ents from 7/2010–8/2014 was made. Massive hemoptysis was defined as an inability to control bleeding (> 300 mL/day) from the endotracheal tube via conven�onal maneuvers, such as bronchoscopy with cold saline lavage, diluted epinephrine lavage, and selec�ve lung isola�on. Owing to all this, it was necessary to disconnect the ven�lator tubing and clamping the endotracheal tube, causing full airway tamponade.

One hundred and eighteen pa�ents were on ECMO, and3 pa�ents had the complica�on of massive hemoptysis. One case was associated with pulmonary catheter migra�on and the other two were spontaneous bleeding events that were propagated by an�platelet agents. Bronchial artery embolization in the interventional radiology suite was performed in all the 3 pa�ents. An�coagula�on was done during the period of massive hemoptysis without any embolic complica�ons. There was no recurrent bleed a�er suitable interven�on. All the three patients were successfully separated from ECMO.

The algorithm for the management of massive hemoptysis, of the pa�ent on ECMO, is demonstrated in Figure 1.

Early iden�fica�on and rapid interven�on are

necessary in the management of pulmonary hemorrhage in

ECMO pa�ents.

Figure 1: Algorithm for the management of massive hemoptysis of the pa�ent on ECMO

Management of hemoptysis on V-A ECMO

Bleeding > 300 mL

Bleeding con�nues,clamp endotracheal tubex 36 hours

Con�nues to bleed,reclamp x 24 hours

Bleeding con�nues

Postemboliza�on bronchoscopy

Repeat

Bleeding con�nues

1) Cessa�on of an�coagula�on- Transfusion- Bronchoscopy

2) Thoracic surgical consulta�on bronchoscopy- Irriga�on dilute epinephrine

If it fails, bronchial blocker x 24 hours

3) Interven�onal radiology- Selec�ve bronchial artery emboliza�on

Consider as early ini�al interven�on- Risk of failure due to lack of �me

DESIGNED TO


8

Ammonia Perfusion Positron Emission Tomography in Pa�ents with Hypertrophic Cardiomyopathy

Source: Yalçin H, Valenta I, Yalçin F, Corona-Villalobos C, Vasquez N, Ra J, et al. Effect of diffuse subendocardial hypoperfusion on le� ventricular cavity size by 13N-Ammonia perfusion PET in pa�ents with hypertrophic cardiomyopathy. Am J Cardiol. 2016 Dec 15;118(12):1908–15.

CONC

LUSI

ON

Microvascular dysfunction causes diffuse subendocardial hypoperfusion and myocardial ischemia which contribute to the development of transient LV cavity dilation in HC.

Introduc�on

Methods

Results

In patients with hypertrophic cardiomyopathy (HC), vasodilator-induced transient le� ventricular (LV) cavity dilation by positron emission tomography (PET) is common. Since most pa�ents with PET-LV cavity dila�on do not have obstruc�ve epicardial coronary artery disease, the researchers hypothesized that vasodilator-induced subendocard ia l hypoperfusion resu l t ing from microvascular dysfunc�on underlies this result.

In order to study the hypothesis, myocardial blood flow (MBF) [subepicardial, subendocardial, and global MBF] and le� ventricular ejec�on frac�on (LVEF) in 104 pa�ents with HC without significant coronary artery disease, using 13NH -PET was quan�fied. Based on the presence/absence 3

of LV cavity dila�on (LVvolume /LVvolume > 1.13) the stress rest

pa�ents were divided into 2 groups.

In 52% of the pa�ents with HC, transient PET-LV cavity dila�on was evident. In pa�ents with HC with LV cavity dila�on; LV mass, stress le� ventricular ou�low tract gradient, mitral E/E', late gadolinium enhancement, and prevalence of ischemic ST-T changes a�er vasodilator were significantly higher. Between the two groups, baseline LVEF

+was similar. But LV cavity dila�on pa�ents had lower stress-LVEF (43 ± 11 vs. 53 ± 10%; p < 0.001), lower stress-MBF in the subendocardial region (1.6 ± 0.7 vs. 2.3 ± 1.0 mL/min/g; p < 0.001), and greater regional perfusion abnormali�es (summed difference score: 7.0 ± 6.1 vs. 3.9 ± 4.3; p = 0.004). An indicator of subendocardial perfusion i.e. transmural perfusion gradient was similar at rest in the

+2 groups (Figure 1). Le� ventricular cavity dila�on pa�ents

had lower stress-transmural perfusion gradients (0.85 ± + -0.22, LV cavity dila�on vs. 1.09 ± 0.39, LV cavity dila�on ;

p < 0.001), sugges�ng vasodilator-induced subendocardial hypoperfusion. The stress-transmural perfusion gradient, global myocardial flow reserve, and stress-LVEF were linked with LV cavity dila�on.

In order to iden�fy the pa�ents with true cavity dila�on versus imaging cavity dila�on in HC, more studies combining PET and cardiac magne�c resonance

imaging following vasodilator infusion are needed.

Figure 1: Comparison of MBF in HC pa�ents with/without LV cavity dila�on in the subendocardial region

LV cavity dila�on presentLV cavity dila�on absent

Transmural perfusion gradient

2.5

2.0

1.5

1.0

0.5

0.0

Sube

ndo/

sube

pi M

BF

Stress

p < 0.001

Rest

*

Issue 3

DESIGNED TO


9

Efficacy of Stress Echocardiography versus Myocardial Perfusion Imaging in the Pa�ents Presen�ng to the Emergency Department with Low-Risk Chest Pain

Introduc�on

Methods

Two frequently used modalities namely stress echocardiography (SE) and myocardial perfusion imaging (MPI) are assigned appropriate use scores across the con�nuum of symptoma�c pa�ents. The purpose of this study was to compare clinically relevant cardiovascular outcomes and downstream u�liza�on linked with SE and MPI in the emergency department pa�ents with low-risk chest pain.

In a retrospec�ve study, health insurance claims data for a na�onal sample of privately insured pa�ents over the period of January 1 to December 31, 2011 were analyzed. The study consisted of pa�ents who reported to the emergency department with primary or secondary diagnosis of chest pain and underwent either SE or MPI. The percentage of pa�ents in each group who underwent

downstream cardiac catheteriza�on, revasculariza�on, repeat noninvasive tes�ng, return emergency department visit with chest pain, and hospitaliza�on for myocardial infarc�on were the primary endpoints (Table 1). The mean length of follow-up in both groups was 190 days. The final analysis included 48,202 pa�ents or 24,101 propensity-matched pairs.

In comparison to SE, MPI was linked with markedlyhigher odds of subsequent cardiac catheterization (adjusted odds ra�o [AOR], 2.15 [95% CI, 1.99–2.33]) and revascularization procedures (AOR, 1.58 [95% CI, 1.36–1.85]) as well as repeat emergency department visits (AOR, 1.14 [95% CI, 1.11–1.19]). The mean cost of downstream care was markedly higher in the MPI group ($2,193.80 vs. $1,631.10, p < 0.0001).

Results

Source: Davies R, Liu G, Sciamanna C, Davidson WR Jr, Leslie DL, Foy AJ. Comparison of the effec�veness of stress echocardiography versus myocardial perfusion imaging in pa�ents presen�ng to the emergency department with low-risk chest pain. Am J Cardiol. 2016 Dec 15;118(12):1786–91.

CONC

LUSI

ON

The findings of this study indicate the need for assessing diagnostic tests based on how they affect hard endpoints since identification of disease may not provide any clinical advantage.

Table 1: Comparison of MPI with SE

Variable MPI SE AOR* P

Cardiac catheteriza�on 3,384 (7%) 9.4% 4.7% 2.2 < .0001

Coronary revasculariza�on procedure 775 (2%) 1.9% 1.3% 1.6 < .0001

Coronary revasculariza�on procedure to cardiac 20.2% 27.7% ---- .0008catheteriza�on ra�o

Repeat emergency department visit 3,891 (8%) 8.1% 8.0% 1.1 .003

Repeat test 7,654 (16%) 16.6% 15.1% 1.0 0.84

Myocardial infarc�on 155 (0.3%) 0.34% 0.30% 1.2 0.20

*Adjusted odds ra�o

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10

SECTION 2

CONC

LUSI

ON

The study demonstrated a higher risk of arterial desaturation in cyanotic patients with high hematocrit undergoing hypothermic CPB.

Which is the most Appropriate Criterion for Size Selec�on of Membrane Oxygenator for Pa�ents with Cyano�c Congenital Heart Diseases: Body

Weight or High Hematocrit?

Contributed by: Ritu Airan, Ujjwal K. Chowdhury, Poonam K. Malhotra, and Balram Airan

FiO /sweep gas was kept constant and hematocrit was 2

maintained between 25–30%. The oxygenator was selected based on the body weight stated in Table 1.

Group I pa�ents had normal SaO2 during CPB. In group II, 32 pa�ents weighing between 20–30 kg and > 30 kg with Terumo SX-10 and SX-18 oxygenators, respec�vely, had system ic arteria l desaturat ion (91–98%) with intraoperat ive hematocrit ranging > 35% and intraopera�ve hematuria (n = 20). In order to achieve op�mal intraopera�ve SaO2 > 99%, further hemodilu�on was performed in pa�ents weighing > 30 kg and by the withdrawal of prime to promote addi�onal hemodilu�on in pa�ents weighing between 20–30 kg. With this background, in 15 of 20 (75%) pa�ents weighing between 8–12 kg to achieve SaO2 between 99–100% pa�ents, Terumo SX-10 was successfully used instead of Minimax.

Results

Aim

Methods

In cyano�c pa�ents, polycythemia causes a decrease in microcirculatory blood flow, thereby causing tissue hypoperfusion and hypoxia. The aim of the study was to compare the intraopera�ve systemic arterial oxygen satura�on (SaO2) in these pa�ents and its associa�on to different-sized membrane oxygenators.

This retrospec�ve study consisted of 130 consecu�ve cyano�c pa�ents between 18 months and 30 years of age (mean ± SD 102.2 ± 80.1) undergoing surgical correc�on (intracardiac repair of tetralogy of Fallot; n = 104; bi-direc�onal Glenn: n = 20; total cavopulmonary connec�on: n = 6) using hypothermic cardiopulmonary bypass (CPB). Group I involved 70 pa�ents who preopera�vely had hematocrit < 60%, whereas Group II involved 60 pa�ents who had hematocrit > 60%. In all the study pa�ents,

Body weight (kg) Oxygenators Priming volume (mL) Flow range (LPM) Group I (n = 70) Group II (n = 60)

8–12 Medtronic- Minimax 800 0.5–2.3 20 5 + 15*

12–30 Terumo SX-10 1,000 0.5–4.0 40 20 + 8

> 30 Terumo SX-18 1,800 0.5–7.0 10 12

*Used Terumo SX-10

Table 1: Selec�on of the oxygenator based on body weight

DESIGNED TO


11

Kine�c-Assisted Venous Drainage on Cardiopulmonary Bypass for Redo Mitral Valve Replacement – A Case Report

Contributed by: K. Thanigainathan, P. Mathavan, Dr. B V Saichandiran

Kine�c-assisted venous drainage (KAVD) is a method of applying a controlled suc�on on the venous line with a kine�c pump to augment the venous drainage. It allows the use of smaller venous cannulae, shorter circuit tubing, and lower priming and blood transfusion volumes.

A 28-year-old male pa�ent was taken up for redo mitral valve replacement for the stuck prosthe�c mitral valve. The es�mated perfusion flow rate for cardiac index

22.4 L/min/m was 4.2 L/min. A�er exposing the femoral region for emergency cannula�on, the pa�ent was prepared for a redo sternotomy. Using standard aor�c cannula�on (22 Fr) and venous cannula�on with femoral vein (20 Fr) and selec�ve SVC cannula (22 Fr – metal �p), CPB was established. In order to accommodate components for KAVD, the CPB circuit was modified. Into the venous line between the venous cannulae and the venous reservoir, a Biomedicus pumphead (Bio-Pump BPX-50, Medtronic) driven by a Biomedicus 550 pump was incorporated. Ten cen�meters before the inlet of the venous pump, a pressure monitoring line was connected to the venous line. Bypass started with the gravity drainage and was not adequate to drain the heart completely. Then KAVD was started by using the kine�c pump motor and increasing the speed to approximately 1,000–1,200 rpm. Due to increased venous siphon, the venous reservoir volume subsequently increased. The highest flow rate was noted and compared with ini�al gravity flow rate. The nega�ve pressure during bypass did not exceed -50 mmHg. A limita�on linked with KAVD is the trapping of air in the centrifugal pump-head. In order to overcome this, a provision was added for bypass line to restore the venous return �ll the centrifugal chamber was to be deaired.

Methods

Result and Conclusion

A unique technique to augment venous drainage in redo surgeries, especially when gravity siphonage fails, is KAVD. Benefits of KAVD are addi�onal flow using a small venous catheter, easier inser�on, a better surgical view, and a smaller incision and thereby decreasing priming volume. The optimal venous siphon is best regulated by determining the assist pump's inlet pressure.

DESIGNED TO


12

SECTION 3

The American Society of ExtraCorporeal Technology Standards and Guidelines in Individuals with Perfusion Prac�ce (2013)

Standards and guidelines for safety devices

Pressure monitoring of the arterial line, cardioplegia delivery systems, and venous reservoir shall be u�lized during cardiopulmonary bypass (CPB) procedure. The pressure monitor should consist of an audible and visual alarm. The pressure monitor should either be servo-regulated to control the arterial/cardioplegia pump or to allow interrup�on to the arterial cardioplegia flow.

During the CPB procedures, a bubble detector shall be u�lized. In order to control the arterial pump or to allow interrup�on of the arterial blood flow, a gross/macro bubble detector shall be used. An audible and visual alarm may be present in the detector system and be posi�oned as per manufacturer's instruc�on for use, to enable �mely iden�fica�on and ac�on.

A level sensor shall be u�lized during CPB procedures using a reservoir. The level sensor shall be either servo-regulated in order to control the arterial pump or to permit interrup�on of the arterial blood flow. An audible and visual alarm may be present on the level sensor and be posi�oned as per the manufacturer's instruc�on, to allow an appropriate reac�on �me and a safe opera�onal volume.

During CPB procedures, temperature monitoring of the arterial ou�low from the oxygenator shall be employed. In order to prevent high arterial outlet temperatures, the temperature sensor shall include an audible and visual alarm.

An arterial-line filter and a one-way valve in the vent line shall be u�lized during CPB procedures. During CPB procedures, a method for retrograde flow shall be u�lized for systems using centrifugal pumps for systemic circula�on. Examples of retrograde avoidance systems are one-way flow valves, hard stop detent controls, electronically ac�vated arterial line clamps, and a low speed visual and audible alarm.

An anesthe�c gas scavenge line shall be u�lized whenever inhala�on agents are introduced into the circuit during CPB procedures. During CPB procedures, hand cranks and a back-up gas shall be available. A back-up battery supply for the CPB machine shall be available during CPB procedures.

Source: Baker RA, Bronson SL, Dickinson TA, Fitzgerald DC, Likosky DS, Mellas NB, et al; Interna�onal Consor�um for Evidence-Based Perfusion for the American Society of ExtraCorporeal Technology. Report from AmSECT's Interna�onal Consor�um for Evidence-Based Perfusion: American Society of

Extracorporeal Technology Standards and Guidelines for Perfusion Prac�ce: 2013. J Extra Corpor Technol. 2013 Sep;45(3):156–66.

DESIGNED TO


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SECTION 4

Bypass Surgery Techniques can be Improved using Synthe�c Heart Valves, Arteries, and Veins

An inven�on of the researchers from the University of Bri�sh Columbia has made it possible for doctors to significantly improve their bypass surgery techniques without depending on animals. The invention was synthe�c heart valves, arteries, and veins made of polyvinyl alcohol hydrogel. Due to polyvinyl �ssue, the surgeons and medical residents could prac�se bypass surgery using the synthe�c material as compared to the current prac�se of using arteries and veins of dead pigs or human cadavers.

The major limita�on of using arteries from human or animal cadavers is that they break down easily if not treated with preserva�ves. On the other hand, synthe�c materia l does not decompose and cannot be contaminated. The material can be manufactured safely

and cheaply. The inven�on is now primarily used for teaching purpose but surgeons and medical residents at the Kelowna General Hospital in Bri�sh Columbia's interior are already using it.

The design of the new synthe�c material gives careful considera�on to how the living human �ssue feels like and resembles it. The arteries from the animals or human cadavers, used for prac�cing bypass surgery, feel different than the living human �ssue. The synthe�c heart valves, veins, and arteries presently used for prac�cing bypass surgery on actual hearts are harvested from pigs. The two researchers are presently working to develop a synthe�c heart using the new material, which would circumvent the necessity to use animal or human cadaver �ssue and organs while prac�cing heart surgery.

Source: Synthe�c heart valves, arteries and veins could vastly improve bypass surgery techniques [Internet] [Updated Sep 1, 2016]. Available at: http://www.news-medical.net/news/20160901/Synthe�c-heart-valves-arteries-and-veins-could-vastly-improve-

bypass-surgery-techniques.aspx. Accessed on Dec 28, 2016.

DESIGNED TO


14

Results

For the transfusion of packed red cells only and any other combinations of blood transfusion, the following predictors were noted, which included factors such as gender, age, weight, type of surgery, reopera�on, unstable angina pectoris, endocarditis, recent myocardial infarc�on, preopera�ve crea�nine level, preopera�ve hemoglobin level, and preoperative platelet count. Preopera�ve hemoglobin level (4.1 to 7.8 mmol/L) is the best predictor for the transfusion of packed cells (Table 1). In case of other blood products, the strongest associa�on was found with type of surgery (aor�c surgery, ventricular septal rupture, and intracardiac tumor).

Methods

The study consisted of 4,022 patients undergoing cardiothoracic surgery between 2008 and 2013. The pa�ents were divided into three groups; no blood transfusion, transfusion of packed red cells only, and any other combina�on of blood transfusion. In all, around 16 variables were tested for their associa�on with the administra�on of homologous blood. The variables linked with blood transfusion were included in a stepwise multinomial logistic regression analysis to find the variables with the strongest associa�on.

Source: de Boer WJ, Visser C, Ganushchak YM. Preopera�ve hemoglobin level: The best predictor of transfusion of packed red cells. Perfusion. 2016 Jul 8.

CONC

LUSI

ON For the transfusion of packed cells alone, any other blood products, or a combination with packed red cells, a group of predictors was identified. In the case of packed red blood cells, the best predictor was identified, and it was different from the predictor associated with other blood products.

The Best Predictor of Transfusion of Packed Red Cells: Preopera�ve Hemoglobin Level

Table 1: Classifica�on of con�nuous variables

Variable Category 1 Category 2 Category 3 Category 4

Length 142–167 cm 167–172 cm 173–206 cm –

Weight 42–71 kg 71–85 kg 85–157 kg –

Preopera�ve crea�nine level 36–72 μmol/L 72–102 μmol/L 103–972 μmol/L –

Preopera�ve hemoglobin level 4.1–7.8 mmol/L 7.8–8.4 mmol/L 8.4–8.9 mmol/L 8.9–11.4 mmol/L9 9 9Preopera�ve platelet count 24–196 x 10 /liter 196–312 x 10 /liter 312–838 x 10 /liter –

Age Age was used as a con�nuous variable since there was a linear rela�onship between the odd ra�os of the different quin�les.

DESIGNED TO


15

Answers: 1–A; 2–A; 3–C; 4–C; 5–A; 6–A; 7–C.

1. An 18-year-old man is brought to the trauma center a�er sustaining a gunshot wound. On physical examina�on, a narrow pressure, jugular venous disten�on, muffled heart sounds, and pulsus paradoxusare reported. What is the most likely diagnosis?

2. A 60-year-old man, recovering in the hospital 15 days a�er undergoing repeat repair of an ascending aor�c aneurysm, has had atrial fibrilla�on for the past five days. As per the laboratory test, the platelet count is

345,000/mm , and this confirms the diagnosis of heparin-induced thrombocytopenia. To prevent the complica�ons associated with the condi�on, an�coagula�on therapy is planned. Before warfarin therapy, the most appropriate an�coagulant therapy is the administra�on of which of the following medica�ons?

3. Which of the following is not a primary responsibility of the perfusionist during CPB?

4. How is the unexpected electrical ac�vity of the heart dealt with during complete CPB?

5. During myocardial fibrilla�on, energy stores are used more quickly than if the heart was in sinus rhythm.

6. The primary objec�ves of CPB are to provide adequate ven�la�on as well as maintain circula�on and perfusion, and temperature regula�on.

7. What is the major concern for the anesthesiologist during CPB when cardioplegic solu�on is administered by the perfusionist?

a. Cardiac tamponadeb. Cardiogenic shockc. Perfora�on of the le� ventricled. Pneumothorax

a. Argatrobanb. Clopidogrelc. Enoxaparind. Ep�fiba�de

a. Ensure circuit tubing is free of air before going on CPB.b. Ensure tubing is connected to pumps to avoid venous air-lock.c. Ensure correla�on between aor�c and radial arterial pressure.d. Maintain an adequate level of anesthesia with potent inhaled anesthe�cs.

a. Excess blood is squeezed out of the heart by hand. b. The surgeon asks the anesthesiologist to administer addi�onal muscle relaxant.c. The surgeon asks the perfusionist to provide an addi�onal cardioplegic solu�on.d. The heart is shocked at 200 J.

a. Trueb. False

a. True b. False

a. It may cause cri�cally elevated blood glucose.b. It may cause fluid overloading which can manifest as pulmonary edema later.c. It may cause ischemia and dysrhythmias because it's cold and has low O content.2

d. It may dilute coagula�on factor concentra�ons to cri�cally low levels.

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